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OBJECTIVES 1. Types of caramel produced; 2. Mechanism and major chemical reactions;

CARAMELIZATION. OBJECTIVES 1. Types of caramel produced; 2. Mechanism and major chemical reactions; 3. Caramel usage. CARAMELIZATION. 1. 1. Significance – about 11% of all colorants used ; around 200 000 tons annual consumption.

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OBJECTIVES 1. Types of caramel produced; 2. Mechanism and major chemical reactions;

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  1. CARAMELIZATION OBJECTIVES 1. Types of caramel produced; 2. Mechanism and major chemical reactions; 3. Caramel usage.

  2. CARAMELIZATION 1 1. Significance – about 11% of all colorants used; around 200 000 tons annual consumption 1850г. – used for the first time in Europe commercially According to the FDA, “The color additive caramel is the dark-brown liquid or solid material resulting from the carefully controlled heat treatment of the following food-grade carbohydrates: dextrose, invert sugar, lactose, malt syrup, molasses, starch hydrolysates and fractions thereof, sucrose.”36 According to JECFA (The Joint FAO/WHO Expert Committee on Food Additives), “Caramel is a complex mixture of compounds, some of which are in the form of colloidal aggregates, manufactured by heating carbohydrates either alone or in the presence of food-grade acids, alkalis or salts; classified according to the reactant used.”41 36. U.S. Food & Drug Administration, Summary of Color Additives Listed for Use in the United States in Food, Drugs, Cosmetics and Medical Devices, Washington, D.C., 1999. 41. JECFA, Combined compendium of food additive specifications, http://www.fao.org.

  3. ! CARAMELIZATION 2

  4. CARAMELIZATION 3 2. Obtaining; phases Raw materials – glucose, glucose-fructose syrup (HFCS), sugar, hydrolysates – corn, wheat, tapioca etc. Chemical reactions involved – hydrolysis, enolization, dehydration, bonds (С-С) rupture, aldolization, cyclization, radical reactions Requirements Hue index – 3.5-7.5 Hue index = 10 log (A510 / A610) Initialcaramelizationtemperaturesofcommoncarbohydrates

  5. ! CARAMELIZATION 4 2. Obtaining; phases I stage – anhydro sugars formation –30min (150-170ºС), 4.5% losses; dimerization – isosachrosan formation; II stage – formation of caramelan – 50min (180ºС), 9% losses Soluble in water and EtOH; bitter taste; tm = 138ºС III stage – formation of caramelen – 80min (180ºС), 14% losses Soluble in water; bitter-sweet taste; tm = 154ºС IV stage – formation of caramelin (huminic type polymers) – 110min (180ºС), Slightly soluble in water; average compositionС125Н188О80

  6. CARAMELIZATION 5 2. Obtaining; phases – caramelization of sucrose

  7. CARAMELIZATION 6 2. Obtaining; phases – caramelization of sucrose

  8. CARAMELIZATION 7 2. Obtaining; phases electronegative caramel (рН 1.5-3.0) – obtained in acid medium, use of inorganic catalysts, 160ºС; electropositive caramel (рН 4.0-5.0) – obtained in presence of ammonia, 120-130ºС. 2.1. Obtaining of anhydro-sugars

  9. CARAMELIZATION 8 2. Obtaining; stages 2.1. Obtaining of anhydro sugars

  10. CARAMELIZATION 9 2. Obtaining; stages 2.2. Obtaining of heterocyclic unsaturated compounds 5-methyl-2-(1-propenyl)- furan α-angelica lactone furfuryl alcohol 5-methyl-2- furanone 5-methyl- 2-furfural 2-propionyl- furan 2-methyl- tetrahydro-3- furanone 2-furfural 2-acetylfuran 2-(2-hydroxy- acetyl)-furan 2,5-diformyl furan isomaltol 5-HMF

  11. CARAMELIZATION 10 2. Obtaining; stages 2.2. Obtaining of heterocyclic unsaturated compounds 5-hydroxymethyl 2-furilic acid furfurylacetate 5-methyl-2- furylic acid 2-(2-oxo- propionyl)furan 5-methyl-2-(2-oxo- propionyl)-furan 1-(2-furyl)-1,2- pentandion 5-(formyloximethtyl)- 2-furfural 5-(acetoxymethyl)- 2-furfural furaneol formoin

  12. CARAMELIZATION 11 2. Obtaining; stages 2.2. Obtaining of heterocyclic unsaturated compounds 5-hydroxy-5,6- dihydromaltol cyclotene Maltol E636 Flavor enhancer 5-hydroxymaltol 5-(5-methyl-2-furfuryl)- 2-furfural 5-(2-furfuryl)- 2-furfural 2,2’-difurilketon difurfurylether bis-(5-formyl-2-furfuryl)-ether

  13. CARAMELIZATION 12 2. Obtaining; stages Some flavors present in the caramels diacetyl (buttery flavor); esters, lactones – rum flavor, sweetish furans – roasted nuts flavor maltol and isomaltol – caramel-like, sweetish, burnt (well-done)

  14. CARAMELIZATION 13 2. Obtaining; stages 2.3. Obtaining of unwanted heterocyclic unsaturated compounds - 4-methylimidazole (4-MeI) - Neurotoxic effects • 2-acetyl-4(5)-tetrahydroxybutylimidazole (THI) Immunosuppressive effects 2.4. Polymerization – aldol condensation reactions

  15. ! CARAMELIZATION 14 3. Application – mainly as food additive

  16. CARAMELIZATION 15 3. Application – mainly as food additive

  17. CARAMELIZATION 16 3. Obtaining

  18. CARAMELIZATION 17 Interactions with other substances Over 700ppm – could lead to aspartame hydrolysis. Adulteration of juices, coffee, honey. Caramelization could be regarded as part of the Maillard reaction and as separate reaction. Info - http://www.food-info.net/uk/colour/caramel.htm

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